From: Jiri Slaby <jirislaby@gmail.com>
To: "\"STenyaK (Bruno González)\"" <stenyak@gmail.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Anssi Hannula <anssi.hannula@gmail.com>,
johann deneux <johann.deneux@gmail.com>,
Linux kernel mailing list <linux-kernel@vger.kernel.org>,
linux-input@atrey.karlin.mff.cuni.cz
Subject: Re: FF layer restrictions [Was: [PATCH 1/1] Input: add sensable phantom driver]
Date: Wed, 21 Mar 2007 14:31:08 +0100 [thread overview]
Message-ID: <4601339C.6010706@gmail.com> (raw)
In-Reply-To: <8e4ff20a0703141218r3add7923n74470b5e16f58c5c@mail.gmail.com>
STenyaK (Bruno González) napsal(a):
> On 3/14/07, Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote:
>> > I have a question: if the force is to be 3D, why only 3 possible
>> values?
>> > What would they be, 3 torques or 3 forces? In the case of car sims (ff
>> > steering wheels), only one axis of torque is usually used (except
>> for 6 dof
>> > platforms, as mentioned).
>> >
>>
>> I wonder if we could somehow extend or augment FF envelope se we could
>> specify a plane for the effect.. Then a vector could be represented by
>> a sum 3 constant effects in 3 separate planes and we could also use
>> spring and other effects as well.
>
> Ideally, afaik we should use:
> -3 values for translation force (linear force): x,y,z components of
> the force vector.
> -4 values for rotation force (torque): x,y,z,w components of the
> quaternion. You can also use euler angles (and i think there are
> another one or two notations), which is just 3 values, but i'm not
> sure it will be a correct decision (due to the gimbal lock problem,
> which may or may not be present in ff devices, dunno).
So, the resolution is? Since I want no longer have out-of-kernel driver, I
need to know how to implement the phantom driver -- merge it `as is', i.e.
control through mmio or rewrite ff layer somehow, and in that case how?
There seem to be only few possibilities:
- new 3D effect, which will be problematic in any other future use, that may
need more than 3 axis. no matter if torques or vector is passed -- depending
on device and programmer (as I need to compute torques from forces in FP).
Maybe struct with 2x 3 axis is OK
- "raw" effect, which may contain more axis, but this is ugly in Anssi's eyes
- something else? (did I forget something)
thanks,
--
http://www.fi.muni.cz/~xslaby/ Jiri Slaby
faculty of informatics, masaryk university, brno, cz
e-mail: jirislaby gmail com, gpg pubkey fingerprint:
B674 9967 0407 CE62 ACC8 22A0 32CC 55C3 39D4 7A7E
next prev parent reply other threads:[~2007-03-21 13:31 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-07 11:36 [PATCH 1/1] Input: add sensable phantom driver Jiri Slaby
2007-03-07 14:47 ` Dmitry Torokhov
2007-03-07 16:38 ` Jiri Slaby
2007-03-07 16:50 ` Greg KH
2007-03-07 16:56 ` Dmitry Torokhov
2007-03-13 16:19 ` Jiri Slaby
[not found] ` <38b3b7c0703131450v2646e63fj2be4b9dda7f928c0@mail.gmail.com>
2007-03-13 22:16 ` FF layer restrictions [Was: [PATCH 1/1] Input: add sensable phantom driver] Jiri Slaby
2007-03-14 15:02 ` Dmitry Torokhov
2007-03-14 16:43 ` Jiri Slaby
2007-03-14 16:45 ` Jiri Slaby
2007-03-14 18:04 ` Anssi Hannula
2007-03-14 18:15 ` Jiri Slaby
[not found] ` <8e4ff20a0703141147n4b690ab8g4cc8138d1ecc94e1@mail.gmail.com>
2007-03-14 19:12 ` STenyaK (Bruno González)
2007-03-14 19:13 ` Dmitry Torokhov
2007-03-14 19:18 ` STenyaK (Bruno González)
2007-03-15 20:51 ` johann deneux
2007-03-15 21:06 ` STenyaK (Bruno González)
2007-03-21 13:31 ` Jiri Slaby [this message]
2007-03-21 13:32 ` Jiri Slaby
2007-03-21 19:02 ` johann deneux
2007-03-21 19:22 ` Dmitry Torokhov
2007-03-21 20:04 ` Jiri Slaby
2007-03-21 22:03 ` johann deneux
2007-03-22 15:50 ` Dmitry Torokhov
2007-03-27 12:20 ` Jiri Slaby
2007-03-27 18:36 ` johann deneux
2007-03-27 20:11 ` Jiri Slaby
2007-03-27 20:43 ` johann deneux
2007-03-27 20:51 ` Jiri Slaby
2007-03-27 21:34 ` johann deneux
2007-03-28 3:08 ` Dmitry Torokhov
2007-03-28 9:28 ` Jiri Slaby
2007-03-28 22:16 ` Jiri Slaby
2007-03-28 22:22 ` Jiri Slaby
2007-03-30 16:46 ` Dmitry Torokhov
2007-03-30 19:11 ` Anssi Hannula
2007-03-15 20:43 ` johann deneux
2007-03-16 16:28 ` Pavel Machek
2007-03-17 7:28 ` johann deneux
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